BTMETER BT-770K Automotive Multimeter with Dwell and Tach

Short answer: A multimeter with the two settings a points tune-up needs: dwell (switchable for 4-cylinder) and tach (600–12,000 RPM through the test leads). Hook it to the coil's negative terminal and ground, and you can read dwell and idle speed together. It's also a full auto-ranging meter for chasing charging problems, bad grounds and dead gauges.

The dwell range for your engine code is in our VW Tune-Up Spec Lookup. Pair this meter with a feeler gauge for the points gap and a basic timing light such as the Innova 3551. If you'd rather have dwell and tach built into the timing light, the Innova 5568 does all of it in one tool.

Vehicle & Engine Fitment

• Air-cooled VW Type 1, 2, 3 and 4: dwell and RPM on points ignition; voltage, current and resistance on any system.
• Porsche 356 and 912: 4-cylinder dwell and RPM.
• Electrical work: generator and alternator output, voltage drops, grounds, gauge senders, fuel injector pulse width on 1975–79 fuel-injected cars.

Key Features & Benefits

• Dwell for 3, 4, 5, 6 and 8 cylinders: set it to 4 for every air-cooled VW.
• Tachometer, 600–12,000 RPM: reads through the test leads. The optional inductive RPM clamp (BT-705A) is not included.
• Auto ranging, 6,000 counts, true RMS: with peak hold and MAX/MIN.
• Hands free: magnetic back, hanger and kickstand to park it on the deck lid or fender.
• Backlit 3" display: readable under the car or in a dim garage.

Technical Specifications

• Part Number: BT-770K
• DC/AC current: to 20 A
• DC/AC voltage: to 1,000 V DC / 750 V AC
• Resistance: to 60 MΩ
• Other functions: capacitance, frequency, duty cycle, pulse width (0.1–10 ms), temperature (thermocouple included), diode, continuity, non-contact voltage
• Included: meter, test leads, thermocouple, zippered carry case
• Warranty: 12 months from the manufacturer

Frequently Asked Questions

• How do I check dwell? Set the meter to dwell, 4 cylinders. Red lead to the coil's negative (terminal 1, the wire to the distributor), black lead to ground. Crank or idle the engine and read it against your spec.
• Does it work on 6-volt cars? Dwell is a timing measurement, not a voltage reading, so a 6-volt car still reads. For voltage tests, just read 6 V instead of 12 V.
• Will it read dwell with electronic ignition? No. Electronic ignitions like Pertronix have no points and no dwell to set.

Installation

Tech Note: If dwell reads high, the points gap is too small; low means the gap is too big. Re-gap, then check dwell again. Changing dwell moves your timing, so always time the engine last.

Explore Related Categories

Doing the full tune-up? Start at the VW Tune-Up Spec Lookup, then browse Tools and our engine parts.